JP2557335B2 - Information recording / playback method - Google Patents
Information recording / playback methodInfo
- Publication number
- JP2557335B2 JP2557335B2 JP59040806A JP4080684A JP2557335B2 JP 2557335 B2 JP2557335 B2 JP 2557335B2 JP 59040806 A JP59040806 A JP 59040806A JP 4080684 A JP4080684 A JP 4080684A JP 2557335 B2 JP2557335 B2 JP 2557335B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- information
- bacteriorhodopsin
- thin film
- recording medium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
- G03C1/00—Photosensitive materials
- G03C1/72—Photosensitive compositions not covered by the groups G03C1/005 - G03C1/705
- G03C1/73—Photosensitive compositions not covered by the groups G03C1/005 - G03C1/705 containing organic compounds
- G03C1/731—Biological compounds
Landscapes
- Engineering & Computer Science (AREA)
- Molecular Biology (AREA)
- Materials Engineering (AREA)
- Biodiversity & Conservation Biology (AREA)
- Biomedical Technology (AREA)
- General Health & Medical Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
- Optical Recording Or Reproduction (AREA)
- Thermal Transfer Or Thermal Recording In General (AREA)
- Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
Description
【発明の詳細な説明】 〔発明の技術分野〕 この発明は、光ディスクメモリなどにおける光記録に
関するもので、生体材料を光記録媒体として用いること
により、情報の階調信号としての書き込み，読み出しが
容易で、かつ書き換えができるようにした情報の記録・
再生方法に関するものである。Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to optical recording in an optical disk memory or the like. By using a biomaterial as an optical recording medium, writing and reading as a gradation signal of information can be easily performed. And record information that can be rewritten
It relates to a reproduction method.
従来、光記録媒体としては、第１図に示すものがあっ
た。図において、１は金属蒸着膜、２は金属蒸着膜１に
レーザビームを照射して形成された細孔、３はレーザビ
ームの未照射部分、４はガラス基板である。この従来の
光記録媒体に情報を記録するには、レーザビームを金属
蒸着膜１に照射して行なう。レーザビームが照射された
部分は、温度が上昇し、金属部が溶解脱離して細孔２が
生じ、これによりレーザビーム未照射部３を“0"とし、
レーザビーム照射部を“1"として両者を区別でき、ディ
ジタルメモリとしての２値が得られる。Conventionally, an optical recording medium has been shown in FIG. In the figure, 1 is a metal vapor deposition film, 2 is a pore formed by irradiating the metal vapor deposition film 1 with a laser beam, 3 is a portion not irradiated with a laser beam, and 4 is a glass substrate. Information is recorded on this conventional optical recording medium by irradiating the metal vapor deposition film 1 with a laser beam. In the portion irradiated with the laser beam, the temperature rises, the metal portion is melted and desorbed, and pores 2 are generated, whereby the laser beam non-irradiated portion 3 is set to “0”,
The laser beam irradiation unit is set to "1" so that the two can be distinguished from each other, and a binary value as a digital memory can be obtained.
従来の光記録媒体は以上のように構成されているた
め、この従来の光記録媒体を用いた情報の記録・再生方
法では、一度記録した信号は書き換えることができず、
また信号は、“0",“1"の２値しかとり得ず、従って階
調記録、即ちアナログ記録は不可能であった。Since the conventional optical recording medium is configured as described above, in the information recording / reproducing method using the conventional optical recording medium, the signal once recorded cannot be rewritten,
Further, the signal can take only two values of "0" and "1", and therefore gradation recording, that is, analog recording was impossible.
この発明は、上記のような従来の光記録媒体を用いた
情報の記録・再生方法における欠点を除去するためにな
されたものであり、高度好塩菌の生体膜中に存在してい
る色素蛋白質であるバクテリオロドプシンの薄膜を光記
録媒体として用い、光の照射による該薄膜の光学的性質
の変化を利用して情報の記録，再生を行なう全く新規な
情報の記録・再生方法を提供することを目的としてい
る。The present invention has been made in order to eliminate the above-mentioned drawbacks in the information recording / reproducing method using the conventional optical recording medium, and is a pigment protein present in the biological membrane of highly halophilic bacteria. To provide a completely new information recording / reproducing method for recording / reproducing information by using a thin film of bacteriorhodopsin as an optical recording medium and utilizing a change in optical property of the thin film by irradiation of light. Has an aim.
まず、この発明の原理及び作用を図について説明す
る。First, the principle and operation of the present invention will be described with reference to the drawings.
バクテリオロドプシンは高度好塩菌（Halobacterium
halobium）の生体膜中に存在している色素蛋白質であ
り、光反応を行なうことが知られている。この光反応に
関してはまだその全容は解明されていないが、光反応中
間体が数種類発見されている。Bacteriorhodopsin is a highly halophilic bacterium.
halobium) is a chromoprotein present in the biological membrane and is known to undergo photoreaction. Although the whole picture of this photoreaction has not yet been elucidated, several types of photoreaction intermediates have been discovered.
そこで本発明者は、バクテリオロドプシンを安定な固
定膜として機能させ、光反応の進行を制御可能であれ
ば、バクテリオロドプシン膜を光記録媒体として使用で
きることに着目した。特にバクテリオロドプシン膜はそ
の光反応が可逆的であること、又、反応の進行を照射光
の強度で制御できる可能性があることから、このバクテ
リオロドプシン膜を用いて階調記録が可能で、かつ書き
換え可能な光記録媒体が得られることを見い出した。Therefore, the present inventor has noticed that the bacteriorhodopsin film can be used as an optical recording medium if the bacteriorhodopsin film functions as a stable fixed film and the progress of the photoreaction can be controlled. In particular, since the photoreaction of the bacteriorhodopsin film is reversible and there is a possibility that the progress of the reaction can be controlled by the intensity of irradiation light, gradation recording is possible using this bacteriorhodopsin film, and It has been found that a rewritable optical recording medium can be obtained.
即ち本発明者は、上記考察に基づき鋭意研究を行なっ
た結果、バクテリオロドプシンをガラスやシリコンウエ
ハ等の基板上に薄膜として製膜することにより光記録媒
体を作成し、該薄膜の光反応による光学的性質の変化し
た状態を情報の記録，再生用信号として用いることが可
能であることに着目してこの発明の創作した。That is, the present inventor, as a result of earnest research based on the above consideration, produced an optical recording medium by forming a thin film of bacteriorhodopsin on a substrate such as glass or a silicon wafer, and produced an optical recording medium by optical reaction of the thin film. The present invention was created paying attention to the fact that it is possible to use a state in which the physical properties have changed as a signal for recording and reproducing information.
第３図及び第４図は本発明者が上記着目点に基づいて
行なったバクテリオロドプシン膜の光の吸収スペクトル
に関する実験結果を示す。FIGS. 3 and 4 show the results of experiments conducted by the present inventor on the basis of the above points of interest regarding the light absorption spectrum of the bacteriorhodopsin film.
第３図はバクテリオロドプシン膜の光反応前の光の吸
収スペクトルを示し、該吸収スペクトルの測定は−195
℃で行なった。また第４図はバクテリオロドプシン膜の
光反応前の吸光度と光反応後の吸光度との差である差吸
収スペクトルを示し、この際の光反応は−195℃におい
て緑色レーザ光（波長500nm）を照射することにより行
なった。FIG. 3 shows the light absorption spectrum of the bacteriorhodopsin film before the photoreaction, and the absorption spectrum was measured at -195.
Performed at ° C. Fig. 4 shows the difference absorption spectrum which is the difference between the absorbance before the photoreaction and the absorbance after the photoreaction of the bacteriorhodopsin film. The photoreaction at this time was irradiated with a green laser beam (wavelength 500 nm) at -195 ° C. It was done by doing.
第３図及び第４図からバクテリオロドプシン膜は、光
反応前においては500〜600nmの波長域に強い吸収帯を持
つが、光反応後−195℃において安定な上記バクテリオ
ロドプシンの反応中間体は、600nm近傍を除く600〜750n
mの波長範囲では光反応前より強い吸光度を、そして約6
30nmの波長に吸収ピークを持ち、また600nm近傍を除く5
00〜600nmの波長範囲での吸光度は光反応前と比較し弱
いことがわかる。また、実験によりこの反応中間体は、
波長700nm以上の赤色光を照射すると反応前の状態に戻
り、第３図に示した吸収スペクトルをもつようになるこ
とがわかった。From FIGS. 3 and 4, the bacteriorhodopsin film has a strong absorption band in the wavelength range of 500 to 600 nm before the photoreaction, but the reaction intermediate of the bacteriorhodopsin that is stable at -195 ° C. after the photoreaction is 600 to 750n except near 600nm
In the wavelength range of m, the absorbance was stronger than before the photoreaction, and about 6
Has an absorption peak at a wavelength of 30 nm, and excludes the vicinity of 600 nm5
It can be seen that the absorbance in the wavelength range of 00 to 600 nm is weaker than that before the photoreaction. In addition, by experiment, this reaction intermediate was
It was found that when irradiated with red light having a wavelength of 700 nm or more, the state before the reaction was returned to have the absorption spectrum shown in FIG.
更に緑色照射光の照射時において、その強度又は照射
時間を制御することにより、第４図に示した光反応前後
での差吸収スペクトルの差吸光度を所望の特性にできる
ことがわかった。Further, it was found that by controlling the intensity or irradiation time of the green irradiation light, the differential absorption of the differential absorption spectrum before and after the photoreaction shown in FIG. 4 can be made to have a desired characteristic.
したがって、緑色照射光による情報の書き込みにより
変化したバクテリオロドプシン膜の光吸収能の変化を、
この膜に上記の600nm近傍を除く500〜600nm又は600〜75
0nmの波長範囲の光を当ててその反射光か透過光の光強
度を測定することにより検知することで、記録情報の読
み出し、つまり情報の再生を行うことができる。Therefore, the change in the light absorption capacity of the bacteriorhodopsin film, which was changed by the writing of information by the green irradiation light,
In this film, 500-600 nm or 600-75 excluding the above 600 nm
By detecting the light intensity of the reflected light or the transmitted light by applying light in the wavelength range of 0 nm, the recorded information can be read out, that is, the information can be reproduced.
以上の実験結果により、バクテリオロドプシン膜を用
いて情報の階調記録，再生あるいは書き換えを行なうに
は以下の方法によればよいことがわかった。From the above experimental results, it was found that the following method can be used for gradation recording, reproduction or rewriting of information using the bacteriorhodopsin film.
（１） 情報の記録を行なうには、バクテリオロドプシ
ン膜の書き込み光反応を起こす記録用照射光としてレー
ザ光（緑色光または青色光）を用いる。(1) To record information, laser light (green light or blue light) is used as irradiation light for recording which causes a writing light reaction of the bacteriorhodopsin film.
（２） バクテリオロドプシン膜を用いた光記録媒体を
−120℃以下の一定温度に保持した状態で上記記録用照
射光を上記薄膜に照射して書き込み光反応を起こさせ、
該光反応後の状態を書き込み状態とし、さらに該書き込
み状態にある光記録媒体を−120℃以下の一定温度に保
持することにより、上記書き込み状態を安定に保持せし
める。(2) The thin film is irradiated with the recording irradiation light in a state where the optical recording medium using the bacteriorhodopsin film is kept at a constant temperature of −120 ° C. or lower to cause a writing light reaction,
The state after the photoreaction is set to the written state, and the optical recording medium in the written state is held at a constant temperature of −120 ° C. or less, so that the written state can be held stably.
（３） 光書き込み後、該記録情報を再生するには、50
0〜600nm又は600〜750nmの波長範囲の再生用照射光を光
記録媒体に照射し、該光の反射率又は透過率から記録情
報を再生する。(3) To reproduce the recorded information after optical writing, 50
An optical recording medium is irradiated with reproduction irradiation light having a wavelength range of 0 to 600 nm or 600 to 750 nm, and recorded information is reproduced from the reflectance or the transmittance of the light.
（４） 光書き込み後、該記録情報を消去するには、該
消去したい部分に赤色レーザ光（波長＞700nm）を照射
すればよく、これにより上記反応中間体は光書き込み前
の初期状態に戻り、その結果所望の部分の書き込み信号
が消去される。(4) To erase the recorded information after optical writing, the portion to be erased may be irradiated with red laser light (wavelength> 700 nm), whereby the reaction intermediate returns to the initial state before optical writing. As a result, the write signal in the desired portion is erased.
（５） 情報の階調記録を行なうには、光書き込み用照
射光の強度又は照射時間を制御すればよい。(5) In order to perform gradation recording of information, the intensity or irradiation time of the irradiation light for optical writing may be controlled.
次に本発明の実施例を図について説明する。 Next, an embodiment of the present invention will be described with reference to the drawings.
第２図は本発明の一実施例方法により情報が記録され
た光記録媒体を模式的に示したものであり、図におい
て、５はガラス基板10上に形成されたバクテリオロドプ
シン薄膜、６はレーザビーム未照射部、7,8,9はレーザ
ビーム照射部である。FIG. 2 schematically shows an optical recording medium on which information is recorded by the method of one embodiment of the present invention. In FIG. 2, 5 is a bacteriorhodopsin thin film formed on a glass substrate 10, and 6 is a laser. Beam non-irradiated portions, and 7, 8 and 9 are laser beam irradiated portions.
上記記録媒体に情報を記録するには、−120℃以下の
一定温度において上記バクテリオロドプシン膜５の照射
部7,8,9となるべき部分にこの順番で強度の大きい青色
レーザ光を照射する。するとこれにより上記照射部7,8,
9の光学的性質、例えば光の反射率，透過率が該照射率
7,8,9の順番で大きく変化し、該光学的性質が変化した
状態を情報の記録状態として情報の階調記録が実現され
る。In order to record information on the recording medium, a portion of the bacteriorhodopsin film 5 to be the irradiation portions 7, 8, 9 is irradiated with a blue laser light having a high intensity in this order at a constant temperature of −120 ° C. or lower. Then, by this, the irradiation unit 7,8,
The optical properties of 9 such as light reflectance and transmittance are the irradiation rate.
Gradation recording of information is realized by using the state in which the optical characteristics are changed in the order of 7, 8 and 9 and the optical property is changed.
そして該光記録媒体から情報を再生するには、該光記
録媒体に500〜600nm又は600〜750nmの波長範囲にある再
生用照射光を照射する。すると上記レーザビーム照射部
7,8,9における上記再生用照射光の反射率又は透過率は
未照射部６における反射率又は透過率とは上記信号強度
に応じて変化しており、従ってこれから情報を再生でき
る。Then, in order to reproduce information from the optical recording medium, the optical recording medium is irradiated with reproduction irradiation light having a wavelength range of 500 to 600 nm or 600 to 750 nm. Then the laser beam irradiation part
The reflectance or transmittance of the reproduction irradiation light at 7, 8 and 9 is different from the reflectance or transmittance at the non-irradiated portion 6 depending on the signal intensity, and therefore information can be reproduced from this.
また、上記光記録媒体の記録情報を消去するには、薄
膜５の情報を消去したい部分に消去用照射光として赤色
レーザ光（波長＞700nm）を照射すればよく、これによ
り該照射部の光の反射率，透過率は上記情報記録前の値
に戻り、これにより記録情報を消去できる。そしてしか
る後上記記録方法により再度情報を記録すれば、これに
より情報の書き換えが実現できる。In order to erase the recorded information on the optical recording medium, a portion of the thin film 5 where the information is to be erased may be irradiated with red laser light (wavelength> 700 nm) as the irradiation light for erasing. The reflectance and the transmittance of the recording medium return to the values before the information recording, and the recorded information can be erased. Then, if the information is recorded again by the recording method, the information can be rewritten.
なお、上記バクテリオロドプシン薄膜は、純粋なもの
に限られるものではなく、例えば脂質あるいはポリスチ
レン等の合成高分子物質を含むバクテリオロドプシン薄
膜であってもよい。The bacteriorhodopsin thin film is not limited to a pure thin film, and may be a bacteriorhodopsin thin film containing a synthetic polymer substance such as lipid or polystyrene.
以上のようにこの発明に係る情報の記録・再生方法に
よれば、雰囲気温度を−120℃以下の一定温度とし、基
板上にバクテリオロドプシンの薄膜を形成してなる光記
録媒体に対し情報に応じて強度又は照射時間を変化させ
た緑色又は青色レーザ光を照射し、該光の照射により上
記薄膜の光学的性質が階調状に変化した状態を上記情報
の記録状態とし、該記録状態にある薄膜に、600nm近傍
の波長を除く500〜600nm又は600〜750nmの波長範囲のレ
ーザ光を照射し、その時の光の反射率又は透過率から情
報を再生するようにしたから、情報の記録および再生が
できる効果がある。As described above, according to the information recording / reproducing method of the present invention, the ambient temperature is set to a constant temperature of −120 ° C. or less, and an optical recording medium formed by forming a thin film of bacteriorhodopsin on a substrate is used according to the information. Is irradiated with green or blue laser light whose intensity or irradiation time is changed, and a state in which the optical property of the thin film is changed in gradation by the irradiation of the light is set as the above-mentioned recording state of the information. The thin film is irradiated with laser light in the wavelength range of 500 to 600 nm or 600 to 750 nm excluding the wavelength near 600 nm, and the information is reproduced from the reflectance or transmittance of the light at that time. There is an effect that can be.
第１図は従来の光記録パターンの一例を示す図、第２図
は本発明の一実施例方法による光記録パターンを示す
図、第３図はバクテリオロドプシン膜の光反応前の吸収
スペクトルを示す特性図、第４図はバクテリオロドプシ
ン膜の光反応前後の光の差吸収スペクトルを示す特性図
である。 ５……バクテリオロドプシン薄膜、10……ガラス基板。FIG. 1 is a diagram showing an example of a conventional optical recording pattern, FIG. 2 is a diagram showing an optical recording pattern according to an embodiment of the present invention, and FIG. 3 is an absorption spectrum of a bacteriorhodopsin film before photoreaction. FIG. 4 is a characteristic diagram showing a differential absorption spectrum of light before and after a photoreaction of the bacteriorhodopsin film. 5: Bacteriorhodopsin thin film, 10: Glass substrate.
Claims (1)
し、基板上にバクテリオロドプシンの薄膜を形成してな
る光記録媒体に対し情報に応じて強度又は照射時間を変
化させた緑色又は青色レーザ光を照射し、該光の照射に
より上記薄膜の光学的性質が階調状に変化した状態を上
記情報の記録状態とし、該記録状態にある薄膜に、600n
m近傍の波長を除く500〜600nm又は600〜750nmの波長範
囲のレーザ光を照射し、その時の光の反射率又は透過率
から情報を再生することを特徴とする情報の記録・再生
方法。1. A green or blue laser in which the ambient temperature is set to a constant temperature of −120 ° C. or lower and the intensity or irradiation time is changed in accordance with information on an optical recording medium formed by forming a thin film of bacteriorhodopsin on a substrate. Irradiating light, the state in which the optical properties of the thin film is changed in gradation by the irradiation of light is the recording state of the information, and the thin film in the recording state has 600n
A method for recording / reproducing information, which comprises irradiating laser light in a wavelength range of 500 to 600 nm or 600 to 750 nm excluding wavelengths near m, and reproducing information from the reflectance or transmittance of the light at that time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59040806A JP2557335B2 (en) | 1984-03-02 | 1984-03-02 | Information recording / playback method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59040806A JP2557335B2 (en) | 1984-03-02 | 1984-03-02 | Information recording / playback method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60185228A JPS60185228A (en) | 1985-09-20 |
| JP2557335B2 true JP2557335B2 (en) | 1996-11-27 |
Family
ID=12590880
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59040806A Expired - Lifetime JP2557335B2 (en) | 1984-03-02 | 1984-03-02 | Information recording / playback method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2557335B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6896945B2 (en) | 2001-08-22 | 2005-05-24 | Bayer Aktiengesellschaft | Optical data carrier comprising a phthalocyanine dye as light-absorbent compound in the information layer |
| US6926943B2 (en) | 2000-04-04 | 2005-08-09 | Bayer Aktiengesellschaft | Use of light-absorbing compounds in the information layer of optical data carriers, and optical data carriers |
| US7041354B2 (en) | 2001-03-28 | 2006-05-09 | Bayer Aktiengesellschaft | Optical data carrier comprising a cyanine dye as light-absorbent compound in the information layer |
-
1984
- 1984-03-02 JP JP59040806A patent/JP2557335B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6926943B2 (en) | 2000-04-04 | 2005-08-09 | Bayer Aktiengesellschaft | Use of light-absorbing compounds in the information layer of optical data carriers, and optical data carriers |
| US7041354B2 (en) | 2001-03-28 | 2006-05-09 | Bayer Aktiengesellschaft | Optical data carrier comprising a cyanine dye as light-absorbent compound in the information layer |
| US6896945B2 (en) | 2001-08-22 | 2005-05-24 | Bayer Aktiengesellschaft | Optical data carrier comprising a phthalocyanine dye as light-absorbent compound in the information layer |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60185228A (en) | 1985-09-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3451752B2 (en) | Optical recording medium | |
| US5088086A (en) | Optical recording medium and the method of recording, reading, and erasing information using it | |
| JP2000339753A (en) | Phase transition recording medium for draw type application | |
| JPS63155436A (en) | Information recording medium | |
| JPS63167428A (en) | Information memory device | |
| JP2557335B2 (en) | Information recording / playback method | |
| JPH0447892B2 (en) | ||
| JP2527436B2 (en) | Optical recording method and optical recording medium | |
| JPH02152029A (en) | Optical information recording medium | |
| JPH0422256B2 (en) | ||
| JPS60217541A (en) | Optical disk | |
| JPH03200957A (en) | Rewritable photochromic optical disk | |
| JPH0317832A (en) | Recording and reproducing system for optical disk | |
| JPS60263353A (en) | Optical disk | |
| JPS63306090A (en) | Optical information memory medium | |
| JPH0980681A (en) | Photochromic optical recording medium | |
| JP2814759B2 (en) | Multi-level optical recording medium and its reading method | |
| JPH05210849A (en) | Rewritable type optical disk and method for recording and reproducing the same | |
| JPH083912B2 (en) | Novel optical recording medium and manufacturing method thereof | |
| JPS61170929A (en) | Optical information reproducing device | |
| JPH01137438A (en) | Optical disk information recording and reproducing device | |
| JP2002298438A (en) | Optical recording medium | |
| JPH02178086A (en) | Optical recording medium | |
| JPH04248128A (en) | Optical information recording method and recording medium | |
| JPH03292630A (en) | Information recording method |